Anyone know of a coin shop / bullion dealer with an XRF machine in the Dallas metro? 1 1

[Taylor7]

I've called around but the only shop with an XRF I could find is on the other side of the metro from me, and has their machine in the back which totally defeats the purpose of doing XRF where the customer can see the results themselves. I have a few coins I think are on the wrong planchet but can't afford the price of grading + metallurgic testing. 

Also interested in hearing about at home tests that don't damage the coin if you know of any. Obviously weighing the coin is the first, but the tolerances on coins like Kennedy halves are greater than the difference between 40% silver and Copper-Nickel clad. 

There's also the tissue paper test but I don't want to clean anything and the dark toning makes that test hard to interpret. 

[RWB]

Observationally, most dealer-owned and jeweler-owned XRF units are not reliable. The devices require regular maintenance and calibration, plus validation testing. They also have to be used by someone knowledgeable in correct technique and in the limitations of the equipment.

[Taylor7]

surely they can tell the difference between copper-nickel and silver, even if not calibrated. I can understand it being off a few %, or mistaking the chorine in paper for trace amounts of palladium since their emission lines are close, but they should be able to tell me if a coin is 95% copper vs 75% vs 10% 

if not, how would you recommend testing a coin for its metal content without paying to send it in?

[Oldhoopster]

As @RWB said, analytical equipment is only as good as the people running it.  They need regular calibration, and don't even think about using the handhelds for any trace analysis.  The algorithms are set up for bulk materials

If you think you have an off composition planchet, check the weight. Simple enough

[Taylor7]

A copper-nickel clad Kennedy Half ways 11.36g and a silver clad weighs 11.50g. Their tolerance is much greater than 0.14g, so its really not that simple. Maybe I'll find a way to do a high accuracy resistivity measurement, or get a ~300nm UVC LED and something that fluoresces and make an apparatus to reflect that light off the coin, since silver is much less reflective around that wavelength. 

 

 

 

[RWB]

On 10/10/2022 at 7:17 PM, Taylor7 said:

surely they can tell the difference between copper-nickel and silver, even if not calibrated. I can understand it being off a few %, or mistaking the chorine in paper for trace amounts of palladium since their emission lines are close, but they should be able to tell me if a coin is 95% copper vs 75% vs 10% 

if not, how would you recommend testing a coin for its metal content without paying to send it in?

Yes, they can even in the hands of a coin dealer. But you can do that by looking or weighing.

[J P M]

Taylor7...  From the questions you are asking I am going to take a wild guess and say you have some 65 Kennedy's that don't show copper on the edge and you want to know if they are the silver 65 Kennedy's ?

[VKurtB]

… or a 1971 that he thinks contains silver. 

[Taylor7]

I have a lot of coins, both American and foreign, I suspect are on wrong planchets, and coins aren’t the only thing I want to test. 
 

So how do I calibrate an XRF? I might just pretend to be a service tech or print the user manual and procure whatever samples I need for calibration. 
 

All I asked was what shops in the Dallas metro have one. My efforts to call around have failed, thought this community might know. Might as well extend the search to anywhere in Texas. 

[VKurtB]

On 10/11/2022 at 4:29 PM, Taylor7 said:

I have a lot of coins, both American and foreign, I suspect are on wrong planchets,

Trust me - if you think you have “a lot of coins” on wrong planchets, it’s you that are wrong. They are exceptionally rare. 

[Taylor7]

On 10/11/2022 at 4:37 PM, VKurtB said:

Trust me - if you think you have “a lot of coins” on wrong planchets, it’s you that are wrong. They are exceptionally rare. 

I’m aware of that, but I’m going through collections I inherited and bought at estate sales not just roll hunting, so it’s quite possible I’m looking at a lifetime of coins set aside because they “look funny”. XRF is a rather new development, like grading, and these collections pre-date those and have already yielded some rather impressive finds so testing is worth pursuing, I just can’t afford $100+ to send each suspected coin off. And like I said, coins aren’t all I want to test. 

[Just Bob]

Have you tried a specific gravity test?

[RWB]

Several places will rent hand held XRF pre-calibrated for certain metals. But I suspect the companies will want a hefty deposit, fee, insurances and proof of competency in handling an X-ray emitter. A university lab might allow a grad student to test item for you - especially if it fits within his/her thesis.

Edited October 12, 2022 by RWB

[VKurtB]

On 10/11/2022 at 4:48 PM, Taylor7 said:

I’m aware of that, but I’m going through collections I inherited and bought at estate sales not just roll hunting, so it’s quite possible I’m looking at a lifetime of coins set aside because they “look funny”. XRF is a rather new development, like grading, and these collections pre-date those and have already yielded some rather impressive finds so testing is worth pursuing, I just can’t afford $100+ to send each suspected coin off. And like I said, coins aren’t all I want to test. 

What is that makes you think you are looking at wrong planchet coins?

[EagleRJO]

On 10/11/2022 at 9:44 PM, VKurtB said:

What is that makes you think you are looking at wrong planchet coins?

If you do a YT search for "Get Rich with Pocket Change" the enlightenment you seek will likely be found.

[EagleRJO]

On 10/11/2022 at 6:10 PM, Just Bob said:

Have you tried a specific gravity test?

I was wondering about the same thing as it's pretty easy to do with an accurate scale and a few basics, combined with taking accurate measurements of coins. However, this can be time consuming for many coins and it seems like the op is looking for a way to quickly go through many coins to look for blank errors.

Why not just go to the dealer in your area who has the equipment in the back? Do you really need to see the results to the point of trying to come up with your own evaluation methods?

Edited October 13, 2022 by EagleRJO

[Taylor7]

I found a way to test for silver at home that's cheap, easy, reliable, relatively fast (few hours), can test many coins at once, and is 100% accurate (unlike a scale). 

Lo and behold, this 1971-D Kennedy half erroneously struck on a 40% silver planchet! Perhaps the finest known! I'll be making a listing for it on the BST forum shortly. 

My digital scale from Amazon (maxus brand) says this coin weighs 11.32g. Funny though, even though I've calibrated it it seems to underweigh halves and overweigh pennies. Regardless, the tolerance on halves is so wide ***weighing the coin is not an accurate test***

RWB, thank you for making me doubt XRF. Indeed I was told a silver coin was cu-ni. Even have a photo of the machine results. Not sure if it was the shop clerks error or if they should unplug its ethernet cable, if you know what I mean. (I would if I ran a jewelry/coin/bullion shop). 

So how does this test work? Simply place the coin in a sealed container for several hours with some chopped up hardboiled egg whites (not touching, just in the same container). The sulphur in one of the proteins will evaporate and tone the silver in mere hours. I set the container in sunlight to speed it up. I had the coins I tested partially sticking out of their mylar flips so it would be easier to see the difference (see the gold tone on the upper right third in the photo).

The only drawback is this is probably considered artificial toning, so it will need restoration when it does get sent in for grading. 

Sure enough, at least one of the coins I suspected was silver is indeed, and what a gorgeous one at that. Auction records (that I've found so far) are $9,900 for an AU 50-something example and $13,000 for an MS61 on 4-20 2018. 

What do you think mine will grade? Not waiting to grade it to sell it though! Pazuzu's student loan payments are past due!

How do I search auction records for error coins by the way? Is there a way to view populations of them on any of the grading companies sites?

 

 

Edited October 22, 2022 by Taylor7

[EagleRJO]

Which peer reviewed industry accepted scientific journal was this "test" obtained from, and what were the metallurgical qualifications of the authors. Anything else is just worthless home brewed junk science you could get from a 3 sec YT search [and not a substitute for industry accepted SG and other tests].

And who is going to just take someone's word based on junk science that it's a rare error and spend that kind of money without a cert from one of the big boys. And if it was a legit error the coin is probably impaired now which may not even be able to be conserved. Sorry, I have to call um like I see it.

Edited October 31, 2022 by EagleRJO

[Taylor7]

if you weren't aware, there is an amazing website called "google" that lets you perform a search of all the websites on the internet. This other useful website, "youtube" even has countless videos on a wide variety of subjects. Using either you would find this is introductory chemistry stuff and not the subject of peer reviewed scientific literature of the past few centuries. Don't feel bad, frankly I'm embarrassed I didn't think of doing this sooner. 

 

You could also just do the experiment yourself. You're on a coin forum so chances are you have some junk silver and cu-ni clad coins lying around. You may not know this, but those coins and also the green paper rectangles they are often exchanged for can be used at places called "stores" as a standard unit of barter for goods like an "egg" (they usually come in packs of 12 in the refrigerated part of the store (the cold part). Eggs are a common food in most parts of the world and come from "chickens", which are a type of "bird", but if you can't find a store you might also try following a bird back to its nest. If you don't know what a bird is, its the animal commonly depicted on the reverse of american coinage. You will need a sealable container, also known as "tupperware", a small pot to boil the eggs with. Water, and a stove (gas or electric will do, but you should probably ask for help from your parent as fire and boiling water can burn you, FYI). 

 

Any other questions?

 

Edited October 22, 2022 by Taylor7

[EagleRJO]

Yup, junk science like I suspected, without even measuring the SG which is simple [and doesnt damage the coin]. Good luck with that.

Edited October 22, 2022 by EagleRJO

[Taylor7]

I like how you edited your comment to include mention of YouTube while I was still writing mine. Funny. Probably related to why I would unplug my XRFs Ethernet cable if I had one. All you can say is junk science now that I have proof of your meddling you petulant clown. 
 

by the way, the other silver ‘71-D half graded by NGC also weighed only 11.3g. SG wouldn’t tell you the thickness of the silver vs clad layer anyway, which probably varies a lot and accounts for the weight variability. Your attempts to discredit me and discourage people from transacting with me are hilariously immature. You should probably seek psychiatric care for your obsession with someone you don’t know. Cease and desist this nonsense. 

[EagleRJO]

I put brackets around my edit if that helps clarify your misconception.

[Taylor7]

On 10/22/2022 at 5:22 AM, EagleRJO said:

I put brackets around my edit if that helps clarify your misconception.

As I pointed out, with silver clad vs cu-no clad SG is not a useful test because of the unknown thickness of the layers, but you’ve made it clear you’re not here to have a useful discussion or learn, simply to discredit me. 

[Oldhoopster]

I think this guy is just trolling.  He said the XRF said its cupronickel, but he doesn't believe it, but has no trouble believing an egg test.  Just another lonely troll trying to get a rise out of the members

 

[Oldhoopster]

On 10/22/2022 at 3:29 AM, Taylor7 said:

I found a way to test for silver at home that's cheap, easy, reliable, relatively fast (few hours), can test many coins at once, and is 100% accurate (unlike a scale). 

Lo and behold, this 1971-D Kennedy half erroneously struck on a 40% silver planchet! Perhaps the finest known! I'll be making a listing for it on the BST forum shortly. 

My digital scale from Amazon (maxus brand) says this coin weighs 11.32g. Funny though, even though I've calibrated it it seems to underweigh halves and overweigh pennies. Regardless, the tolerance on halves is so wide ***weighing the coin is not an accurate test***

RWB, thank you for making me doubt XRF. Indeed I was told a silver coin was cu-ni. Even have a photo of the machine results. Not sure if it was the shop clerks error or if they should unplug its ethernet cable, if you know what I mean. (I would if I ran a jewelry/coin/bullion shop). 

So how does this test work? Simply place the coin in a sealed container for several hours with some chopped up hardboiled egg whites (not touching, just in the same container). The sulphur in one of the proteins will evaporate and tone the silver in mere hours. I set the container in sunlight to speed it up. I had the coins I tested partially sticking out of their mylar flips so it would be easier to see the difference (see the gold tone on the upper right third in the photo).

The only drawback is this is probably considered artificial toning, so it will need restoration when it does get sent in for grading. 

Sure enough, at least one of the coins I suspected was silver is indeed, and what a gorgeous one at that. Auction records (that I've found so far) are $9,900 for an AU 50-something example and $13,000 for an MS61 on 4-20 2018. 

What do you think mine will grade? Not waiting to grade it to sell it though! Pazuzu's student loan payments are past due!

How do I search auction records for error coins by the way? Is there a way to view populations of them on any of the grading companies sites?

 

 

So you don't trust the XRF data that said it was copper nickel, but you did a test that damages the surface of the coin (your BST ad said you would dip it if desired ).

[Sandon]

   I had previously refrained from participating in this thread because the original poster had simply asked a question as to where he can find a certain type of machine, which i can't answer.  He now insists that he has a 1971-D Kennedy half dollar struck on a 40% silver planchet even though weighing the coin and testing it on the machine have both given him the "wrong answer"!

    My first question to @Taylor7is this: If you believe you have such a coin and want to sell it for thousands of dollars, why haven't you sent it to a reputable third-party service such as NGC, PCGS, or ANACS? In today's numismatic marketplace it is highly unlikely that any serious collector or dealer would purchase such an item uncertified, especially without an opportunity for in-person inspection.  Like the Supreme Court, these services may not be final because they are infallible, but they are infallible because they are considered final!  If it is what you think it is, it would be well worth the cost!

   My second question is why you have posted no photo of the coin except for the obverse, which looks like any other 1971-D Kennedy half dollar.  The first thing I'd notice that would make me suspect that the coin was on a silver clad 1965-70 planchet would be that the edge isn't the mostly mint red or brown color of a pure copper core but is rather the slightly darkened silvery color of a 20% silver core as found on these silver clad pieces.  May we see a photo of the edge?

[EagleRJO]

On 10/22/2022 at 6:43 AM, Taylor7 said:

As I pointed out, with silver clad vs cu-no clad SG is not a useful test because of the unknown thickness of the layers

Not true. The US Mint has very tight tolerances on planchets, and an Au clad coin has a very different SG than a Cu-Ni coin if you would have actually taken the time to look that up and check reputable sources for mint data like the Coin World Almanac.

On 10/22/2022 at 11:00 AM, Oldhoopster said:

I think this guy is just trolling.

No, I think he is baiting.

Edited October 31, 2022 by EagleRJO

[Taylor7]

The physics of XRF is quite sound, what I don’t trust is the firmware, the stores network security, or their staff. I’ve been targeted by a lot of pathetic online and offline harassment and believe this is one more example. 
 

The other NGC graded example also weighs only 11.3g so the assertion the tolerances are tight is demonstrably false. 
 

if grading companies were infallible and or final there would be no cross grading, regrading, or crack out game. 
 

if the people harassing me can hack a jewelry stores XRF or convince them to deceive me, what makes you think they can’t do the same to a grading company or mail service. 
 

I’ll post photos of the edge shortly

[Taylor7]

Not one congratulations on the find. Not one thanks for the useful info. Just pathetic anger at seeing someone you dislike succeed. 
 

This is what y’all look like right now:

[J P M]

On 10/22/2022 at 6:58 PM, Taylor7 said:

The physics of XRF is quite sound, what I don’t trust is the firmware, the stores network security, or their staff. I’ve been targeted by a lot of pathetic online and offline harassment and believe this is one more example. 
 

The other NGC graded example also weighs only 11.3g so the assertion the tolerances are tight is demonstrably false. 
 

if grading companies were infallible and or final there would be no cross grading, regrading, or crack out game. 
 

if the people harassing me can hack a jewelry stores XRF or convince them to deceive me, what makes you think they can’t do the same to a grading company or mail service. 
 

I’ll post photos of the edge shortly

Well I hope the Kennedy it is a winner. Now the big question is ? Why are people targeting you. No one here knows you?